Hydroelectric Idea

Joined: Oct 10, 2011
Posts: 25

posted Jan 17, 2012 23:01:39

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I highly doubt that I'm the first person to think of this, however I haven't seen anything on the forum that is similar enough. So I thought I would start my very own (and first ) Topic. And observing that this forum has many intelligent, well grounded and chalk full of common sense people with diverse backgrounds, I could use some input. Now from what I've read most micro hydro doesn't really produce enough electricity, at least not a notable amount. Especially run of river hydro (not using weirs or dams, which are generally out of the realm of most property owners anyway). Eventually I stumbled upon Wirtz pumps, (specifically this website regarding them http://lurkertech.com/water/pump/tailer/ ) now for those of you who do not wish to read that entire article I will summarize. It is basically a set of coils with decreasing diameter mounted to a water wheel with the output running through the center of the wheel, every time the wheel spins (slowly as it is powered by the river) it picks up water as well as air which is compressed as it journeys into the ever smaller diameter of coils. The air then decompresses as it travels out the output tube adding extra distance. So basically you get a low RPM high lift system capable of moving a lot of water (depending on the size of the wheel/tube) a fair distance. So getting ahead of myself as usual I did a bunch of spreadsheets for various sizes of wheels/pipes to calculate the lift/flow of water with various RPMS. Now I'm thinking that if you happen to own land near a river (which is an eventual goal of mine anyway) there is great potential there. The basic Idea is to run a pump or two' output hose way up a hill and then back down to the turbine where afterwards it will re enter the river. Now I've done plenty of calculations in regard to the actual pumps themselves and their capabilities (basically everything you can do short of building one, and I may decide to do that this summer as well), but I would like input as to potential ideas/problems ect. Specifically if anyone has had experience with hydroelectric power generation, regarding how to size turbines ect, and a lot of the electrical know how.

I have a few considerations (perhaps foolish, do tell!) in regards to pooling the water. But for the moment I'd like to hear any feedback/interest before I go blathering on . Oh I should also mention that apparently there are large ones of these that have been built in Africa to serve the purpose of irrigation.

The power that is obtained from any hydro installation is completely dependent on the flow and head available and is many times the cheapest per watt option compared to PV or wind. Even a small yield of 50 watts equals 50 x 24hrs =1.2 kwhs. If you have no head available but you have a large enough stream / river, you would get more power from a tethered prop style hydro unit then you would yield from any pump/storage/hydro scheme. There is just too much loss from energy conversion to make a pump/storage/hydro setup worthwhile. If your curious about hydro yields for different heads and flow , you can use the online calculator at www.powerspout.com

Joined: Oct 10, 2011
Posts: 25

posted Jan 18, 2012 16:52:01

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Right but in this situation (provided you have the hills, although I suppose you could make an earthen ramp) you're using the pressure of the pump to create the head. The lift on these pumps is pretty great, and the amount of volume is only limited by the size of the piping and overall size of your pump. However you could have more than one pump in order to double your volume. And since even the very turning of the pump is powered by the river you should get decent returns. Another benefit is that these are run of the river devices that do not inhibit the flow of life on the rivers. And a little off topic this pump (as well as the fact I'm in the middle of Mycelium running by Stamets) gives me interesting ideas of using the power of the river combined with large mycelial mats to clean the water.

According to the Powerspout site the 40 feet of head at 2.7 gallons per minute (3900 gals/day) would produce 4 watts. I have to believe you could generate more than that directly from the water movement in the stream.

A pair a what shift?

Joined: Oct 10, 2011
Posts: 25

posted Jan 19, 2012 04:33:41

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Even the smallest pump I calculated (at a diameter of 6 FT, or I should say the out piping has a diameter of 6 ft, not the entire structure) using 1 inch tubing would be capable of 2.9L (.76 gal) per rotation per coil set with a max head lift of 130 ft. You could fit many more sets of coils on it than one. The numbers only get larger the bigger you build it. For example a 12 foot pump using the same 1 inch tubing would be capable of 11.6 L (3.06 gal) per rotation per coil set with a max head of 441 ft. Even if the 12 footer was on a lazy river and turned only three times a minute with two coil sets you'd be looking at almost 20 gpm with a huge amount of head. Now I know you're probably looking at these numbers and wondering at the calculations, they are rather laborious and long, but I assure you they are correct and will gladly provide them if asked for (I didn't want to turn away what little interest there seems to be in this ;P). The only limit I can forsee on the number of sets of coils is the possibility that at some point they would become far too heavy to turn easily (or possibly overcome the buoyancy of the pontoons if it is on one of the floating options).

I'm not an engineer but it seems to me that whatever amount of power it takes to pump it up the hill it certainly can only exert the same force coming back down. It takes 2.23 hp to pump 20 GPM at 441 ft. of head. 2.23 hp is 1663 watts. If there is enough force in the stream to power a pump which takes 1663 watts to run why not just run a generator directly? Or are you saying it does not take 1663 watts to pump 20 GPM at 441 ft of head due to the pump configuration?

Unless you're creating some sort of hill top resevoir ,there is absolutely nothing to be gained by pumping water up there. There will be frictional losses.

There are instances where elevating the water makes sense. Tidal power is often abundant at the wrong time of day, so water is pumped to storage ponds where it waits for peak load. Niagara falls is drained of most of its water at night when the tourists are asleep. This water is stored until needed. There are losses in both of these examples. No energy is gained by pumping it up hill. There are frictional losses and a small amount of evaporative losses.

I failed to mention (I think?) that this wirtz pump can be mounted on pontoons, (or just attached to a river bank) and its rotation is powered by waterwheel type action, using the flow of the river.

Cj: The lift comes from the changes in pressure within the pump, these pumps are particularly good for slow moving rivers where other hydro would not suffice. You get high lift from very slow RPMs, the distance it can pump is only limited by the number of coils within the pump, which increase the pressure of the water/air as it passes through towards the exit. I am not aware of any slow turning water wheel type run of river hydro that is capable of generating a substantial amount of electricity (other than this), if you have any links I'd love to see them. There is a bonus alone in the lift due to the air decompressing as it travels out of the tube, according to the calculations on the website I linked in my OP it's about 25%.

Dale: I couldn't say for sure but I would imagine the frictional losses of water in a pipe are fairly minimal? Perhaps I'm in error there. A reservoir at the top of the hill was part of the idea (I did not share it in the OP because I figured I had been confusing enough lol), I have a couple ideas in regard to that, which I will try to blather out in as rational a form as I can! I'll start with the less elaborate one and then try to explain the other.

Plan 1: The pump carries the water to a reservoir (probably at a distance shorter than its maximum lift) where before its added to the reservoir it passes through its first turbine. Since the line is pressurized I imagine it will turn it just fine, however since it will be coming out in spurtz (water, air, water, air ect) I wonder how effective this will be. Perhaps the air will also be enough to spin the turbine. I imagine at any rate there are devices with capacitors that could even out the fluctuation in energy provided there. It then pools in the reservoir (possibly multiple sets of pumps can congregate at one) where it is channeled back down to the riverside to the second turbine before being released back into the river. The advantages of this would be you could harness it twice, and someone please correct me on this because I might be in error but my assumption is that the weight of the water in the reservoir (provided it is big enough) will help the acceleration as it travels down the pipe to the river?

Plan 2: Is the same as plan 1 except this time (and feel free to call me crazy) the line carrying the water up the hill from the pump is suspended in air by cables from nearby tree's (providing of course that there are any). This get up allows for yet another (although smaller) chance to capture power from the water. The first turbine meets the cable 30 or so feet in the air (on a tree or tower I guess you could build if you really wanted to), this turbine is powered mostly by the fact that the line is pressurized (just like the first turbine in plan 1), you then get to add a 2nd turbine near the reservoir for when this same water drops via gravity from turbine 1 to turbine 2. It wouldn't be as much as turbine 3 (by the river) since its only a 30 foot or so drop. So in theory you could potentially harvest the energy of this water three times.

Rick: I am pretty darned confused about what you are saying, but maybe its the hour of the day, I'll re-read it after a nap.

I am willing to draw diagrams if these descriptions have been sub par, and I apologize for any confusion I am casting as I just got out of work and am rather fatigued. I thank all of you for your continued interest it is nice to have someone other than the GF to bother with this haha.

Check with an expert on frictional losses. They can be substantial. You mentioned the weight of the water in the resevoir. Penstock pressure is determined by the head, that is the height of drop. It dosen't mater whether the resevoir is a hot tub or a 10 sq. mile lake, if the height is equal then the pressure will be equal.

I was equally baffled by an earlier reply. I think it may involve magic and fairy dust. And possibility some ganja.

because Wirtz pumps operate at low speeds, frictional losses in that part of the system will be relatively small. and the larger the pipe used, the lower will be the friction. these pumps are a great, accessible solution to pumping water.

if electricity is what you're after, though, I'm not sure this is the answer. seems like it would be much simpler to generate directly from the water wheel and forget the Wirtz pump. the pump would add a layer of complexity that wouldn't provide any more usable energy. and Pelton wheels aren't cheap.

but do build a Wirtz pump for the water. I think they're great and I hope to build one myself.

I disagree with you a bit there tel, I think there's more potential than you think. In what I outlined in plan 2 it seems possible to capture the water three times. And while that might be a bit more on the overkill side of things, in plan 1 you can still capture twice. Now I'm not saying that capturing it just from the water wheel isn't a viable option, but I don't know what sort yields are possible from that, I'll have to look into it. And it just occurs to me that it may be possible to both pump the water AND capture the power from the turning of the wheel (course that might be pushing it as to what the rivers capable of doing).

Edit: Oh I forgot to add, that for purely water pumping potential I have a separate thought to perhaps use it in conjunction with large mycelium mats ect. I am just in love with the idea of the river supplying its own power to clean itself. Thoughts?

tel jetson
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Joined: May 17, 2007
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Location: woodland, washington

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posted Jan 21, 2012 10:02:26

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Oroborus Hatfield wrote:I disagree with you a bit there tel, I think there's more potential than you think. In what I outlined in plan 2 it seems possible to capture the water three times. And while that might be a bit more on the overkill side of things, in plan 1 you can still capture twice. Now I'm not saying that capturing it just from the water wheel isn't a viable option, but I don't know what sort yields are possible from that, I'll have to look into it. And it just occurs to me that it may be possible to both pump the water AND capture the power from the turning of the wheel (course that might be pushing it as to what the rivers capable of doing).

you would be capturing and transforming the kinetic energy of the water three times. the trouble is that all the kinetic energy of the water comes from the kinetic energy provided by your water wheel (which comes from the kinetic energy of the river). you can't get more energy out than that water wheel puts in, which is why I figure it would be so much simpler to just use the water wheel coupled directly to your generator. that way you've only got the one (or two, counting river to wheel) opportunity for loss instead of four (or five, counting river to wheel).

Oroborus Hatfield wrote:Edit: Oh I forgot to add, that for purely water pumping potential I have a separate thought to perhaps use it in conjunction with large mycelium mats ect. I am just in love with the idea of the river supplying its own power to clean itself. Thoughts?

sounds like it has potential. the only issues I see are that it would probably warm the water. this would only be a problem if the scale is fairly large, but that's also probably the scale you would need to clean a significant portion of the river. placing the works in deep shade would mitigate both warming and evaporation. it should be very easy to take samples before and after the water passes through the mycelium to check for change. I think you should try it out.

Joined: Oct 10, 2011
Posts: 25

posted Jan 22, 2012 04:45:04

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You're only capturing the kinetic energy of the river once, when it first comes out. The second and third time the energy is provided by acceleration due to gravity. And providing the river has the strength to do it, you could conceivably also run a rig off the side of it, just to capture the rotational energy provided by the river.

In regards to the mycelium mats another consideration I have is perhaps having an artificial stream (fueled by the pumps) that perhaps just have innoculated straw bales along the edges

Oroborus, you are correct that you capture the kinetic energy from the river once, but you are converting that kinetic energy into potential energy by pumping it uphill. The potential energy you now have in the reservoir is equal to the kinetic energy you captured from the river, minus the losses in the pump and piping. Once you send the water down from the reservoir, you are converting that potential energy back into kinetic energy, via gravity as you mentioned. This kinetic energy is now equal to the potential energy stored in the reservoir minus the evaporation losses at the reservoir and friction losses in the piping.

The net result is that you now have less energy available for power production at the river than you started with. To maximize your efficiency, you want to minimize your energy conversions. As other posters have said, you'd be better off driving your generator directly from the water wheel, rather than pumping uphill.

However, this pump is a good idea for getting irrigation water up to dry locations when you have a slow moving/low gradient river. If you have a higher gradient river, it may be easier and more cost effective to use a ram pump.

Check out our blog at http://circlempc.blogspot.com where we discuss our experiences as we revitalize our family's ranch utilizing Permaculture principles and values.

tel jetson
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Joined: May 17, 2007
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posted Jan 22, 2012 12:50:15

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to play on your name a little bit, Oroborus, your plan is a bit like eating one's own tail in an attempt to gain weight. at first blush it seems like such a ready source of nutrition, but it just won't work out.

an alternative might be to build one water wheel and use it for both a Wirtz pump and to directly power a generator. might take a bigger wheel than either separately would, but you'll cover both of the objectives you've mentioned: moving water and generating electricity.

Electricity produced through the hydroelectric energy generation method is without any pollution or harmful environmental effects. Neither are any dangerous greenhouse gases emitted, nor burning of fossil fuels is necessary to generate electricity this way. Hydroelectric power plants generate renewable energy. Building this type of an energy plant is not very costly and there are government grants which help relax the financial burden of building a power station.

I think this is an awesome idea. The amount of energy needed to pump the water to the reservoir is irrelevant. As long as the reservoir is high enough to generate decent head and you've got enough Wirtz pumps to keep it full, I see no reason why you couldn't generate considerable electricity with this setup.
A lot more than you would ever get from hooking a generator directly to an under-shot waterwheel floating on a slow, lazy river. You pretty much eliminate the possibility of large debris damaging your turbine too.

well, if you had a water wheel, like the Wirtz pumped, and just geared it up to your generator speed, you'd lose less than in the conversion pumping up to a reservoir and then flowing back down to a turbine.

That's what people are saying. It takes a lot of power to turn that Wirtz pump, so instead of converting it a few times and losing a lot of your energy, just convert it once.

This idea would work but I would say if you have a river it should be at the bottom of a list of possibilities.

1) if you can find a section of your river with 10' of drop you could build a sluice and use something like a Powerspout LH.
2) if you have a lot of flow but very little head, an undershot paddle wheel generator will still give you some power.
3) If you are set on pumping water, a ram pump is more efficient, easier to hide and has fewer moving parts.
4) The beauty of a coil pump is the low-tech components. Some wood and a couple hundred feet of PE pipe is mostly what you need. The sticky part is the rotating flange...